Due to flow non- uniformities in transition region, the thermal entrance region
length can only be determined experimentally by measuring the temperature distribution along the thermal boundary layer.
Fig 3 and 4 shows plot of local convective heat transfer coefficient along dimensionless axial distance from the tube entrance region
. Two Reynold number values are considered 200 and 400 although the Reynold number changes for each test fluid due to change in viscosity but these changes are not much significant and in the range of 100.
Taneda  stated that transition in pipe flow occurs only in the entrance region
Therefore, the region "a" is set as the entrance region
and is set as preset 1 with the initial preset of the PTZ camera.
The stratification phenomenon significantly exacerbates this heat transfer in the entrance region
of horizontal pipes.
It can be inferred that for the teeth development it should be initiated in the entrance region
. In other words, it cannot be initiated in the packing phase.
These results have shown the good agreement with the conventional theories even for the entrance region
of the tube.
Clearly seen from Figure 3, the axial distribution of the Riser-Tube is much more uniform than that of the Riser-Orifice, especially at the entrance region
. Furthermore, the fully developed region is reached early with the multi-tube distributor.
Two-dimensional laminar flow and heat transfer in the entrance region
of a symmetric wavy-channel with constant wall heat flux density which includes fourteen undulations are presented.
 developed the correlation for heat source elements situated in electronic equipment cooling which is the ratio of convective heat transfer co-efficient at entrance and fully developed region which is independent of Reynolds number but dependent only on no of rows situated near by entrance region
. The equation presented is useful or determining the heat transfer for small no of heat source elements.
(2006), the pressure gradient in the entrance region
of a pipe where the flow is developing is different from that which occurs downstream in a fully developed region.
Figure 6 gives the effect of the initial drop size on the extent of drop deformation in the entrance region
and drop breakup in the downstream side of the cylindrical tube (18).